Pivoted rear traction-trucks.



P. E. HOLT.

PIVOTED BEAR TBAGTION TRUCKS. Prmoulox FILED JULY 1, 1909..

1,O'2"1;,99().` Patented Apr. 30, 1912.

PLINY E. iHoLT, OF STOCKTON, CALIFORNIA.

PIVQTED REAR TRACTION-TRUCKS.

Specification of Letters Patent. Patented Apr. 30, v1912.

applicati@ mea July 1, -1909. seal No. 505,386.

To all lwhom t may concern.'

Be it known that I, PLINY E. HoL'r, a citizen of the United States, and residing at 836 West Poplar street, in the city' of Stockton, county of San Joaquin, and State of California,l have invented certain newA and useful-Improvements in Pivoted Rear Traction-Trucks; and I do hereby declare the followingto be a full, clear, and exact .description of the said invention, such as will enable others skilled in the art to which it most nearly appertains to make, use, and practice the same.

This invention relates to improvements in traction vehicles and more particularly to the running gear thereof and consists in the novel construction and arrangementof the parts as hereinafter described. The object sought to be accomplished is to providea horizontally -rigid and vertically Hexible running gear for tractors propelled by traction belt v,mechanisms mounted at each side of the frame.

Broadly, the invention consists of a main frame composed of a rectangular superrame and an isosceles triangular sub-frame havingits apex extended beyond the front and its base extended across and beyond the sides of the super-frame; trucks pivoted to the base beam of the said triangular frame; transverse braces pivoted on the same center as the trucks and extending obliquely across the main frame and'xed to the opposite truck frame; ,buffer springs interposed between the side beams of the triangular frame and the oblique braces at the angle of conjuncture-whereby the main frame remains rigid 'at all times but the pivoted trucks have a limited vertical play without la-teral deviation.

'In the drawings -Figure 1 is a plan view from above of a tractor `frame drawn to illustrate this invention, portions of the frame being broken away and duplicate parts omitted to better disclose the construction. Fig. 2 is a side elevation of the. same.

In detail, the construction consists ofthe n rectangular superframe comprising the side beams, 1 and 2, and the 'end beams, 3 and 4.

' The triangular sub-frame comprises the side'beams, 5 and 6, and the base beam, 7.

The super and sub-frames are rigidly'fxed together at all points of conjunction. The

side beams, 8, of the trucks are provided with the pillow blocks, 9, which a/re pivoted on the pin, 10, in the brackets, v11, fixed to the base beam, 7. The transverse braces, 12 Yand 13, are provide-d at one en'd with the fixed brackets, 14, which engage the pins, 10, which act as a common pivot for the braces andthe trucks. YVhere they pass each other the .braces are bent, as at 15, to` allow sufficient clearance. Thesebraces lie across and are rigidly fixed to the side beams, 8, of their respective .trucks and move as a part thereof. The buffer springs, 16, are interposed between the braces, 12 and 13, and the side beams, 5 and 6, respec-4 tively, of the sub-frame. These springs limit the vertical play of the'trucks and soften the impact of lthe traction belt, 17, with the road.

The driving sprockets, 18, are fixed on the sleeves, 19, journaled in the brackets, 20, which are fixed on'the super-frame. The

driving gears, 21, are fixed-on the sleeves,v

19, and are adapted to engage ay driving mechanlsm, not shown, adapted to be mounted on the super-frame. AThe purpose of mounting the driving sprocket on the same foundation as the driving mechanism is to insure proper meshing of the driving gears. It has been common practice heretofore to mount the driving sprocket in the supporting truck; but this has proven deleterious to the gearing, owing to the possibilities of disalinemnt due to the lostmotion between the supporting trucks and the main fra-me. The floating axle, 22, extends across the machine within the sleeves, 19, to

maintain the alinement of the driving gears.

The gears, 21, are independently driven by independent clutch mechanisms engaging a motive power mechanism not germane to. thls 1nvent10n, and therefore not shown.4

The idle sprockets, 23, are journaled in the forward ends of the trucks.` The endless traction belt, 17, passes `around the driving and the idle sprockets, 18 and 23, and beneath the series of rollers, 24, journaled in the trucks.

The apex of the triangular frame which forms the front of the main frame' is provided wit-h the pivot head, 25, through which the pivot pin, 26, extends and engages thecenter of the front axle, 27. upon which the wheels, 2S, are mounted. The .front axle is swung on its pivot to alter the course of the tractor by the tiller ropes, 29, fixed to the front axle on' opposite si'des of the pivot. The tiller ropes, 29, are wound in opposite directions around the drum, 30, rotated by main frame and attach the supporting trucks rigidly thereto. proven that a rectangular frame cannotl withstand the twisting strains incident to the' of .the tracleverage exerted by the length the ground.

tion surface in contact with This leverage greatly exceeds that 'exerted by a concentrlc wheel which concentrates the strains at the axle; whereas the strains of the traction belt mechanism are constant throughout its length which warp and twist the frame, thereby throwing the machinery` out of alinement and wrecking the structure generally.

The interposition of the triangular frame arrests the twisting and shearing strains that attack the corners 'of the rectangular frame, and it adds an oblique resistance impossible in a simple rectangular frame. The pivoting of theI supporting trucks allows the traction mechanism to accommodate itself to inequalities in the road without lifting the whole weight of the "tractors, or materially affecting' the level of the'main frame.

It is not essential that both trucks be pivoted. It only one truck'was so pivoted it would in a measure lessen the strains on bot-h trucks and on the main frame.l Supposing` for instance, one truck only to 'be pivoted, should the -pivoted truck meet an obstruction it would ride over it without a jarring impact and without lifting the truck on 'the other side. Should the unpivoted truck meet an obstruction it would have to raise the whole frame and subject it to some ar7 but the pivoted truck on the opposite side would retain its full bearing on the ground and escape the twisting strain transmitted through the main frame.

This application for patent is drawn with particular reference to the frame and the traction mechanisms immediately connected therewith Y and constituting the runningfixed to the adjacent truck frame; bilder Experience has noaaeeo springs interposed between the triangular frame and the oblique braces at the points of conjuncture; a wheeled truck pivoted under the apex of the triangular frame; means for steering said wheeled truck; driving sprocketsbracketed to the main. frame; idle ysprockets, trucks; supporting rollers journaled in Said traction trucks; and traction belts encircling said traction trucks and engaging said driving and idle sprockets.

.2. A tractor running gear comprising a main 4frame composed of av rectangular frame A combined with a triangular frame having its apex extended beyond the'front and its base extended across and beyond ythe sides of the said rectangularframe; tractionI trucks pivoted to the base-beam of the said triangular frame; transverse braces pivo ted on the base beam .of the triangular frame and extending obliquely across the main frame ,and fixed to the adjacenttruck frame; buffer springs interposed between the oblique braces and the main frame; a-

wheeled truck pivoted under the apex of the triangular frame;l and means for steering said. wheeled truck.

3. In a-running gear for tractors, a combined rectangular and triangularmain frame; traction belts encircling supplemenjournaled in said traction tal frames pivoted onnthe said main frame and actuated by a driving sprocket journaled therein; braces extending obliquely across the said l.main frame, pivoted thereon and each fixed tothe opposite supplemental frame; and buffer springs interposed between said braces and said main frame.

Il. A tractor running gear comprising a main frame composed of a rectangular fra-me and a triangular frame having its apex and base angles extended beyond the said rectangular frame; a wheeled steering truek'pivoted to the main frame; and traction trucks pivoted at the sides of the main frame.

5. A tractor running gear comprising a triangular main frame, a steering truckpivoted to? the main frame, and traction trucks on eacli side. of the main frame and pivoted to the base beam of said triangular frame, said traction trucks having transverse braces extending across and pivoted on the opposite side of the main frame. Y

6. A tractor running gear comprising a main frame composed of a triangular frame and a',` superposed rectangular frame, the base .beam of the triangular frame projecting beyond the sides of the rectangular frame, traction trucks pivoted at one end to the projecting ends or .said base-beam, and driving sprockets for said trucks.

7.- A tractor running gear comprising a main frame composed-of a triangular frame anda superposed rectangular frame, the base beam of the triangular frame projecting beyond the sidesA of the .rectangular vframe,

traction trucks pivoted at one end to the: projecting ends .of sald base beam, an idler,A

mounted` in the free end of each traction truck, driving sprockets supported by said rectangular frame, and traction belts connecting said driving .sprockets and idlers.

l 8. A tractor running gear comprising a main frame composed of a'triangularrame and a superposed rectangular frame, the base beam of the triangular frame projecting beyond the lsides of the rectangular frame, traction trucks pivoted at one end to the projecting ends of said base beam, braces for said trucks pivotally connected. to the base beam of said triangular' frame, and driving sprockets for said trucks.

9. A tractor running gear comprising a main frame composed of a rectangular frame and a triangular frame having its base beam extending beyond the opposite sides of said rectangular frame, brackets depending from the base beam of said triangular frame pivotpins mounted in said brackets, tractlon trucks pivotally mounted on said pins, and braces for said trucks also pivotally mounted on said pins.

10. A tractor running gear comprising a main frame composed of a rectangular frame and a triangular frame having its` pivotally trucks also base beam extending beyond the opposite sides of said rectangular frameLbrackets depending from said base beam, pivot lpins mounted in said brackets, traction trucks mounted on said pins outside of said rectangular frame, braces' for said frame and a triangular lframe having its' base beam extending` beyond the opposite sides of said rectangular frame, brackets depending frorn said base-beam, pivot pins mounted in said brackets, tractlon trucks pivotally mounted on said pins, a brace pivotally connected at one end to` each pivot pin and having its other end secured to one of said traction trucks on the opposite sideof the frame, and drivingbelts for said trucks mounted independently f the latter.

In testimony whereof, I have hereunto set my hand this 21st day of June 1909.

PLINY E. HoLf-r.

Witnesses.: I Y

JESSE VAN VALKENBURG, PERCY S. SAUNDERS.

pivotally vconnected with said inside of said rectangular` frame, and- 

